1. Field of the Invention
The present invention relates to an improvement in an image display apparatus comprising a flat cathode-ray tube with a number of line cathodes.
More particularly, the present invention concerns an image display apparatus wherein its display screen is divided into a plural number of segments in the vertical direction, and for every those segments one respective electron beam is provided, and in those segments a plural number of horizontal lines are displayed by means of deflecting those respective electron beams in the vertical direction, and each segment has plural number of subsegments or red, green and blue phosphor regions disposed in horizontal direction along which horizontally divided electron beams scan in horizontal direction and constitutes the horizontal lines, thereby, as a whole, a television picture image is displayed.
2. Description of the Prior Art
Hitherto, for an image display apparatus for a television set, a cathode-ray tube having three electron guns or a single electron gun set in a neck part of a bulky cone shaped vacuum enclosure has been used for long time. The shortcoming of the conventional cathode ray tube is a large depth in comparison with the size of the screen face, disabling to provide a flat and compact television set. Though EL display apparatus, plasma display apparatus or liquid crystal display apparatus has been developed, they are not sufficiently usable for practical use because they have problems in their brightness and contrast.
Therefore, intending to obtain an apparatus wherein color television picture images can be displayed by a flat-shaped display device using electron beams, a novel display device has been proposed in a Japanese Patent Application, Sho 56-20618, which was applied by the present applicants. The patent application mentioned above in such that the display plane on a screen of the device is divided into a plural number of segments in the vertical direction, and to each of those segments, one respective electron beam is provided, and in those respective segments a plural number of lines are displayed by means of deflecting those respective electron beams in the vertical direction, and each segment is further divided into a plural number of subsegments in the horizontal direction, and to each subsegment either one of the primary color phosphors of red (R), green (G) and blue (B) is allotted and they are made emit their colors successively by projecting the electron beam thereon, then by controlling the intensity or amount of projected electron beam on those phosphors of R, G and B in responding to the color video signals, as a whole, color television pictures are displayed. Such conventional system has a problem of poor horizontal resolution of displayed picture.